THE PRAGMATICS OF CORRELATION OR HOW MODELS RESHAPE THE GOVERNMENT OF TECHNICAL OBJECTS BRICE LAURENT & FRANÇOIS THOREAU CENTRE DE SOCIOLOGIE DE L’INNOVATION, MINES PARISTECH 4S MEETING, DENVER, 14 TH NOV. 2015

A PROBLEM: QSAR MODELS FOR REGULATION QSAR: Quantitative Structure-Activity Relationship Matters particularly for the toxicity of chemical compounds and pharmaceuticals REACH 2018: inverting the “burden of proof” (reduce costs and animal experimentation) The case of nanomaterials: intensify orders of problems tied to the use of models for regulatory purposes

THE EUROPEAN COMMISSION: CASE BY CASE “A natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50 % or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm nm.” — Recommendation on the definition of a nanomaterial (2011/696/EU) Too vague to enforce (literally out of REACH): so case by case approach

THE EUROPEAN PARLIAMENT Arbitrarily set a defined size limit for delineating the “nanoness” of new materials (1 to 100 nm) General definition by representatives, targeted at a unified « European people » General constraint which neglects actual instrumentation Eventually typical of liberal democracies: consumer information and protection

GROUPING OF CHEMICALS OR READ-ACCROSS Between nominalism and holism; new families through the realm of chemicals Operates on the basis of chosen descriptors (profiling particles) — domain of applicability Depends on chosen endpoints (which effects to consider? Fish toxicity, skin irritations, …?) Problems: assess correlations (what does it say?), stability of compounds Models must avoid over-fitting and under-fitting

CONCLUSION: A FLEXIBLE GOVERNMENT Regulation based on predictive correlations; changes the very notion of “proof” as in “reverting the burden of proof” The categories and modes of validation are dependent on each grouping of chemicals Experimental approach made of trials and errors (instead of “science speak truth to power”) instead of regulatory categories ex ante